Fabrication, microstructure and ablation resistance of C/C–SiC composites, by using a novel precursor of SiC.

A novel precursor of SiC prepared by mixing boron phenolic resin and hydrolytic solution of tetraethyl orthosilicate was employed to fabricate the ablation-resistant C/C–SiC composites. The pyrolysis behaviors of precursor and the ablation properties of prepared composites were discussed. Results show that during the pyrolyzation process of the precursor, the carbon phase was evenly surrounded by the silica phase, benefitting the occurrence of the carbothermal reaction. The precursor was totally transformed into SiC with the carbon left (7.77–8.11 wt%) after heating at 1600 °C. Due to the unique surrounded structure between the carbon and silica phases, part of the residual carbon was encircled by the generated SiC ceramics. During ablation, the carbon nucleus played a positive role in enhancing ablation resistance of composites by hindering the flow of molten silica. Compared with the composites employed polycarbosilane as precursor, this prepared C/C–SiC composites exhibited a decent anti-ablation performance. [ABSTRACT FROM AUTHOR]